Backers and opponents of ousted Islamist president Mohammed Morsi have called for mass rallies in Egypt on Monday, dpa reported.
The Muslim Brotherhood said the protests across the country would continue to demand the reinstatement of Morsi, who was deposed by the army earlier this month.
"The Muslim Brotherhood vows to persist in peaceful protest action until democratic legitimacy is fully restored," the group said.
"Supporters of constitutional legitimacy are not afraid of death, and stand unarmed in liberty squares across Egypt," said Brotherhood spokesman Gehad El-Hadad.
Defence chief Abdel Fattah al-Sissi, the architect of Morsi's overthrow, said the army was not interested in politics.
"The Armed Forces ... have chosen without reservations to be at the service of the people and enabling them to decide freely what they want," al-Sissi told army officers, according to state-run newspaper al-Ahram.
"The Armed Forces are committing to their role and will not go beyond it."
The Brotherhood denounced Morsi's overthrow as a coup and vowed open-ended protests until he is restored to power.
The army removed Morsi - the country's first democratically elected president - after millions of Egyptians took to the streets demanding his resignation.
The National Salvation Front, a group of liberals and leftists, Sunday called for supporters to gather in Tahrir Square and outside the presidential palace in Cairo to demand fulfilling a military-backed roadmap, which includes amending an Islamist-drafted constitution and holding presidential and parliamentary elections.
Prominent opposition leader and Nobel Peace laureate Mohammed ElBaradei, meanwhile, was sworn in as vice president for international relations.
ElBaradei, a former head of the International Atomic Energy Agency, took the oath of office before interim president Adli Mansour, reported state television.
The ex-diplomat catalyzed a 2011 popular uprising that eventually forced Hosny Mubarak to leave power.
ElBaradei, a winner of the 2005 Nobel Peace Prize, joined late last month a huge protest campaign that demanded Morsi step down, one year after the Islamist leader took office.
Morsi is being held by the army at an unknown location, without any charges so far.
Dozens have been killed in Egypt in clashes since his toppling on July 3.
At least 51 people, mainly Brotherhood supporters, were killed this week in clashes between Islamist protesters and the army outside the headquarters of the Republican Guard in Cairo where Morsi is believed to be held. The army said its troops had acted in self- defence.
Human Rights Watch has called on Egypt's caretaker president to ensure impartial investigations into the incident.
"The military has a track record of resorting quickly and excessively with lethal force to break up protests," Joe Stork, acting Middle East director of the group, said Sunday.
"The government needs to find out who was responsible and ensure they are held accountable if it hopes to show it will respect basic rights during this interim period".